The British architects Peter and Allison Smithson described access balconies as "streets in the sky". Their counterparts can be found in the terraces and balconies that architects Bonhôte Zapata use to structure the residential complex they designed for a building association in Chêne-Bougeries near Geneva. They are literally "squares in the sky" and "rooms in the sky". Five large and open concrete platforms measuring 80 square metres on each level serve as circulation and common spaces for recreational and other uses. In addition, nearly all of the 49 apartments feature generous private balconies. A translucent shell made of pre-weathered fir cladding envelopes both heated interiors and terraces. This emphasizes the homogeneous overall shape of the residential complex and its six houses, slightly offset, with pitched roofs and extremely deep floor plans. A closer look at the facade reveals what kind of rooms are located behind it. The living rooms and bedrooms feature recessed windows with sills only slightly raised above the floors and bronze-coloured, anodized aluminium folding shutters. The balconies are equipped with alternating openings either reaching from floor to ceiling or two-thirds thereof and laminated safety glass railings. The private balconies along the southwestern facade can be shaded by textile roller blinds fixed on the interior side of the timber cladding.
The homogeneous first impression that the new building conveys is deceiving. A diverse set of uses and social mix received priority during the planning process. It was important to the clients that residents live together like in a community. About half of apartments with three to six rooms are subsidized, the others are available at market rates. The building also includes a cluster apartment with eleven rooms, a first in the Canton of Geneva. Aside from the shared terraces the residents can also use an event room, three guest rooms, a workshop and a below-grade parking garage for 58 cars. A nursery for 32 children, a café and a podiatrist's practice are included in the program.
The social interests are complemented by the building association's ecological aims. The residential complex received the Swiss Minergie-P-Eco certification. It is heated by geothermal heat pumps, and the brine circuit of the geothermal probes also enables cooling. The roof surfaces are covered by nearly 600 square metres of photovoltaic and hybrid solar modules. Residents can consume the electricity that is generated here. They created an association for consumption by the owners in order to avoid the requirement of feeding energy into the grid.
